Electronic devices, for example, digital cameras have a plastic housing whose external surface is finely finished. A taking lens is attached to a front surface of the housing and a liquid crystal display (LCD) is attached to a rear surface thereof. The housing contains a circuit board, electronic components, a battery box and the like inside. The housing is fixed to the battery box made of, for example, plastic.
A tapping screw is used for fixing the housing so that the loosening of the screw is avoided. A shank of the tapping screw is inserted from outside of the housing through a hole of the housing. The tapping screw is screwed while an end of the shank is forming an internal thread in a hole of the battery box. Since the tapping screw is in contact with the housing and the battery box both having insulating properties, static electricity may be generated by, for example, friction with the housing, and the tapping screw may be charged.
In general, the static electricity may cause malfunction of the digital camera or destroy the electronic components. As measures to prevent the charging, the components that are easily charged are connected to a negative electrode of a battery (see, for example, Japanese Patent Laid-open Publication No. 11-015054). The tapping screw may also be connected to the negative electrode of the battery via a conductive component. At this time, it is important to maintain good electric contact between the tapping screw and the conductive component.
When a common screw is used, a head of the screw is pressed against the conductive component or a shank of the screw is screwed in the conductive component, to provide good electric contact (see, for example, Japanese Patent Laid-open Publications No. 05-243718 and 08-082316, and Japanese Utility Model Laid-open Publications No. 06-009176 and 07-016366).
In the above digital camera, the shank of the tapping screw is screwed into the insulating battery box. It is therefore impossible to screw the shank in the conductive component. In that case, the conductive component may be put on the housing and interposed between the head of the tapping screw and the housing. However, such conducting assembly may deteriorate the appearance of the digital camera.